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Title: Simulating the universe(s) II: phenomenology of cosmic bubble collisions in full general relativity

Observing the relics of collisions between bubble universes would provide direct evidence for the existence of an eternally inflating Multiverse; the non-observation of such events can also provide important constraints on inflationary physics. Realizing these prospects requires quantitative predictions for observables from the properties of the possible scalar field Lagrangians underlying eternal inflation. Building on previous work, we establish this connection in detail. We perform a fully relativistic numerical study of the phenomenology of bubble collisions in models with a single scalar field, computing the comoving curvature perturbation produced in a wide variety of models. We also construct a set of analytic predictions, allowing us to identify the phenomenologically relevant properties of the scalar field Lagrangian. The agreement between the analytic predictions and numerics in the relevant regions is excellent, and allows us to generalize our results beyond the models we adopt for the numerical studies. Specifically, the signature is completely determined by the spatial profile of the colliding bubble just before the collision, and the de Sitter invariant distance between the bubble centers. The analytic and numerical results support a power-law fit with an index 1< κ ∼< 2. For collisions between identical bubbles, we establish a lower-bound on the observed amplitudemore » of collisions that is set by the present energy density in curvature.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. SCIPP and Department of Physics, University of California, 1156 High St., Santa Cruz, CA, 95064 (United States)
  2. Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, On, M3J 1P3 Canada (Canada)
  3. Department of Physics and Astronomy, University College London, Gower St., London, WC1E 6BT U.K. (United Kingdom)
Publication Date:
OSTI Identifier:
22375832
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; BUBBLES; COLLISIONS; COSMOLOGICAL INFLATION; DE SITTER GROUP; DE SITTER SPACE; ENERGY DENSITY; GENERAL RELATIVITY THEORY; LAGRANGIAN FUNCTION; NUMERICAL ANALYSIS; PERTURBATION THEORY; RELATIVISTIC RANGE; SCALAR FIELDS; UNIVERSE